Effects Of Ground Cover Research Articles

Effect of ground cover on soil carbon storage in a citrus orchard: challenges and preliminary results

Effect of ground cover on soil carbon storage in a citrus orchard: challenges and preliminary results

The effects of ground cover management on fruit yield and quality: a meta-analysis

ABSTRACT An important management strategy for the development of sustainable agriculture in orchards is the management of ground cover. However, there is a knowledge gap regarding the effects of ground cover on fruit yield and quality. We performed a meta-analysis of 580 observations collected from 116 peer-reviewed field studies, to assess the effects of ground cover on fruit yield and quality indicators. Overall, ground cover significantly increased fruit yield, soluble solid content, sugar content, and vitamin C content by 6.98%, 6.77%, 7.83%, and 14.59%, respectively, and significantly reduced fruit acidity by 10.63%. The effects of ground cover on fruit yield and quality were greater in subtropical regions and semi-humid, humid zone. These effects also mostly depended on ground cover types. Cover crops and mulch both significantly improved fruit quality. However, compared to clean tillage practice, legume cover crops substantially enhanced fruit yield while non-legume cover crops significantly decreased fruit yield. This effect was attributed to greater soil moisture and fertility with legume cover crops. Our analysis synthesized the scientific evidence on ground cover management to help orchard managers and policy makers improve orchard fruit yield and quality.

Long-term cover cropping seasonally affects soil microbial carbon metabolism in an apple orchard

ABSTRACT Groundcover management can significantly affect soil microbial metabolic activities, especially carbon metabolism, in apple orchards. However, there have been few studies on the effects of groundcover on the seasonality of soil microbial carbon metabolism. We, therefore, studied soil microbial carbon metabolism in an apple orchard on China’s Loess Plateau under four single species cover crops (the grass Dactylis glomerata L., and the legumes Trifolium repens, Coronilla varia L., Lotus corniculatus L.) during spring, summer and fall. Cover cropping significantly, but differentially, promoted soil microbial carbon metabolism in spring and fall. However, cover cropping leads to a significant reduction of soil moisture in spring and summer due to the competition of soil moisture between the cover crops and apple trees, which probably lead to the changes in types of carbon substances metabolizing by soil microbes in summer. Besides, cover crop significantly enhanced soil organic carbon contents between three seasons while clean cultivation had slight, non-significant effects. The promotion of soil microbial metabolic activities was probably an important mechanism for the carbon accumulation, and we postulate that leguminous cover plants may have significantly different effects, mediated through their root exudates, from grasses on soil carbon contents.

Low canopy cover in a sown Digitaria eriantha Steud. pasture improves establishment of Trifolium subterraneum L.

ABSTRACTIn the summer-dominant rainfall zone of inland northern New South Wales and southern Queensland, tropical grass-temperate legume mixed pastures can provide forage for grazing livestock for most of the year; however, the effect of canopy cover and its interaction with ground cover for regeneration of Trifolium subterraneum (subterranean clover) are not known. An experiment was conducted using established Digitaria eriantha with two levels of canopy cover (defoliated to 0.1 m and undefoliated) and four levels of ground cover (ranging from bare to 75%). Plots were oversown with subterranean clover seed in May–June, and legume establishment and spring herbage production were assessed. Low rainfall throughout the experiment resulted in poor clover establishment and production but seedling densities were significantly higher in the defoliated treatments (14 cf. 6 seedlings/m2). Herbage production was also significantly higher in the defoliated plots (530 cf. 302 kg DM/ha). There was no effect of ground cover. These findings indicate that management strategies that remove excess forage and reduce canopy cover of tropical grass pastures in late summer will maximise regeneration of subterranean clover in autumn.

Mulch and groundcover effects on soil temperature and moisture, surface reflectance, grapevine water potential, and vineyard weed management.

The objectives of this research were to identify alternatives to glyphosate for intra-row (under-trellis) vineyard floor management and to evaluate the potential for intra-row and inter-row (alleyway) groundcovers to reduce vegetative vigor of ‘Marquette’ grapevines (Vitis spp.) in a southeast Nebraska vineyard. The experiment was a randomized factorial design with five intra-row treatments (crushed glass mulch [CG], distillers’ grain mulch [DG], creeping red fescue [CRF], non-sprayed control [NSC], and glyphosate [GLY]) and three inter-row treatments (creeping red fescue [CRF], Kentucky bluegrass [KB], and resident vegetation [RV]). Treatments were established in 2010–2011 and measurements were conducted during 2012 and 2013 on 5- and 6-year-old vines. Soil temperatures were mostly higher under mulches and lower under intra-row groundcovers, compared to GLY. Weed cover in CG, DG, and CRF treatments was the same or less than GLY. At most sampling dates, inter-row soil moisture was lowest under KB. Intra-row soil moisture was highest under DG mulch and lowest under CRF and NSC; CG had the same or lower soil moisture than GLY. Surprisingly, we did not detect differences in mid-day photosynthetically active radiation (PAR) reflectance, despite visual differences among the intra-row treatments. Mid-day vine water potential did not differ among treatments. We concluded it is not necessary to maintain a bare soil strip under established vines in this region, where soil fertility and moisture are non-limiting.

Evaluating remotely sensed plant count accuracy with differing unmanned aircraft system altitudes, physical canopy separations, and ground covers

This study evaluated the effect of flight altitude and canopy separation of container-grown Fire Chief™ arborvitae (Thuja occidentalis L.) on counting accuracy. Images were taken at 6, 12, and 22 m above the ground using unmanned aircraft systems. Plants were spaced to achieve three canopy separation treatments: 5 cm between canopy edges, canopy edges touching, and 5 cm of canopy edge overlap. Plants were placed on two different ground covers: black fabric and gravel. A counting algorithm was trained using Feature Analyst®. Total counting error, false positives, and unidentified plants were reported for images analyzed. In general, total counting error was smaller when plants were fully separated. The effect of ground cover on counting accuracy varied with the counting algorithm. Total counting error for plants placed on gravel (−8) was larger than for those on a black fabric (−2), however, false positive counts were similar for black fabric (6) and gravel (6). Nevertheless, output images of plants placed on gravel did not show a negative effect due to the ground cover but was impacted by differences in image spatial resolution.

The Influence of Nest Density on Nest Predation in Olive Groves Depends on Habitat Features

The simplification and homogenisation of agricultural landscapes has led to dramatic losses of farmland biodiversity. This decline includes passerine populations and one of the mechanisms that may be contributing toward this may be increased nest predation. Ground covers are agri-environmental measures whose objective is to halt the loss of biodiversity by creating high-quality habitat patches embedded in a homogeneous landscape by maintaining herbaceous ground cover within crops. However, although such patches are selected by breeding birds, they may also attract predators, and an increased nest density in small habitat patches would thus result in increased predation rates. We have therefore performed nest predation experiments with artificial nests in order to investigate whether the effect of ground cover on nest predation is density dependent. The experiments were carried out during the breeding season in 2014, in two areas of olive groves in southern Spain. We used two nest density levels, both in olive groves with ground cover and in those where the ground was bare. A total of 420 nests were placed, 226 of which (53.81%) suffered predation. Our results showed that 1) nest predation was density dependent in olive groves with ground cover only with respect to tree nests, while there was no density-dependent predation in bare-ground olive groves of either ground-based or tree nests, and 2) artificial nests placed on the ground were more frequently depredated (65%) than those placed in trees (29%), irrespective of either the presence of vegetation cover or nest density. This study suggests that variations in patterns of nest predation are determined by the identity of nest predators and their specific foraging behaviours in different landscapes and habitats. It also underscores the need to implement agri-environmental measures aimed at the conservation of farmland birds.

Effects of ground cover from branches of arboreal species on weed growth and maize yield

Cultivating maize under systems of alley cropping results in improvements to the soil, a reduction in weeds and an increase in yield. Studies using ground cover from tree shoots produce similar results. The aim of this study was to evaluate the effects on weed growth and maize yield of ground cover made up of 30 t ha-1 (fresh matter) of branches from the tree species: neem (Azadirachta indica A. Juss), gliricidia (Gliricidia sepium (Jacq.) Kunth e x Walp.), leucaena (Leucaena leucocephala (Lam.) de Wit.) and sabia (Mimosa caesalpiniifolia Benth.). Two treatment groups (cultivars and weed control) were evaluated. The cultivars AG 1041 and AL Bandeirantes were subjected to the following treatments: no hoeing, double hoeing, and ground a cover of branches of the above species when sowing the maize. A randomised block design was used with split lots (cultivars in the lots) and ten replications. The cultivars did not differ for green ear or grain yield. Double hoeing was more effective than ground cover at reducing the growth of weeds. However, both weeding and ground cover resulted in similar yields for green ears and grain, which were greater than those obtained with the unweeded maize.

Effect of different ground cover management on spider mites (Acari: Tetranychidae) and their phytoseiid (Acari: Phytoseiidae) enemies in citrus orchards

We determined the effect of ground cover on phytoseiid predatory mite populations and the potential biological control of Panonychus citri (McGregor). Results showed that citrus trees with ground cover contained higher population densities of predatory mites and provided better regulation of P. citri than trees in bare soil. The ground cover Ageratum conyzoides L. performed better than Palspalum notatum Flugge in sheltering phytoseiid mites.

The effects of ground cover and shading on an outdoor thermal environment in an apartment complex

A comfortable outdoor environment can be achieved through well-designed physical planning, which includes the layouts of buildings, covering materials, grass, trees, water areas, etc. In this study, the outdoor environments of an apartment complex were measured quantitatively. The paving, grass and water areas were chosen to analyse the effects of ground cover on the outdoor environment. An unsteady-state computational fluid dynamics (CFD) simulation was also conducted with the same conditions as the measurement. In order to obtain the reliability and limitation of the simulation, the results of the measurement and the simulation were compared. The effects of changing the green area, including the grass and the trees, to 15% and 50% were analysed by the simulation method. Depending on the ground cover, the air temperature slightly changed. However, the mean radiant temperature (MRT) of the grass area was lower than that of other areas. Especially the shaded area showed a very low MRT and thus thermal comf...

Effect of ground cover on splash and sheetwash erosion over a steep forested hillslope: A plot-scale study

The contributions and relationships of erosion by splash and overland flow over a steep slope in a Japanese beech forest in plots with different percentages of ground cover were examined. Three erosion plots (2 m wide × 5 m long) with average understory coverage of 1%, 45%, and 94% were installed. Sediment transported by rain splash and by overland flow was sampled separately. For the plots with sparse, moderate, and high understory coverage, the average proportions of splash soil to total soil erosion during the monitoring period were 16%, 32%, and 18%, respectively. A significant correlation between the amount of splash soil and precipitation was found in the plots with 1% and 45% understory coverage, whereas no statistical relationship was identified for the plot with high understory coverage. At the sparse ground cover plot showing the largest sediment movement, the contribution of splash transport decreased with increasing precipitation. The amount of sheetwash erosion was significantly correlated with the amount of splash soil under the condition of sparse ground cover. This relationship was more pronounced during high precipitation events and the rainy season. Splash contribution to the sediment transport was in the range of 0.8%–76.7%, 2.8%–81% and 2.1%–60.8% for plot with high, moderate and low ground cover, respectively. The sparse ground cover showed the largest variation of splash and sheetwash contribution in soil erosion. This variability was due to variation in ground cover and soil surface wetness condition which led to a variation of detachment and non-linear relationship of sheetwash splash.

The effect of ground cover or initial organic carbon on soil fungi, aggregation, moisture and organic carbon in one season with oat ( Avena sativa) plots

The unique capacity of fungi to efficiently sequester carbon in aerobic conditions, presents a way to maximize OC gain in agricultural systems. Oat ( Avena sativa) was planted in the temperate climate of southern Ontario, Canada to study factors affecting soil organic carbon (OC). The plots varied with initial OC from 25 to 68 g kg −1 or with ground cover of differing decomposability (alfalfa ( Medicago sativa) growing from seed, dried oat straw, dried hay and compost) on high OC soil (60–70 g kg −1). The soil was analysed for correlation of changes in soil aggregation, moisture, OC, fungal hyphal number and length and distribution of organic matter by mass and OC in density fractions within the growing season. At harvest, soil OC and moisture were increased only in plots with ground cover. Total hyphal length was not significantly different with ground cover treatment at harvest, and did not correlate with soil aggregation and soil OC. However, the number of hyphae with >5 μm diameter (primarily mycorrhizal fungi) correlated with % OC in ground cover plots while the number of hyphae <5 μm (primarily saprophytic fungi) correlated with % OC without ground cover in the gradient of initial soil OC. Mycorrhizal hyphae may be important to the increases in soil OC from surface treatment, although there was no treatment effect of mycorrhizal occurrence on the oat roots. This microcosm study, with growing and dried ground cover, suggests surface management may a simple and inexpensive means in agriculture to increase soil moisture and OC that benefits farmers as well as reducing atmospheric CO 2.

Effects of ground cover (straw and compost) on the abundance of natural enemies and soil macro invertebrates in vineyards

Abstract1 Herbicides are commonly applied under grapevines in Australia to remove weeds and thereby to avoid water loss through transpiration.2 Interest in sustainability promotes a reduction in chemical inputs, including herbicides, leading to trials with surface mulches to suppress weeds.3 Surface mulches may also influence the abundance of a range of invertebrates. Potentially, an increase in natural enemies will contribute to pest control and encourage a reduction in pesticide application.4 We used three trapping methods and direct soil sampling to assess invertebrates at ground level, in the canopy and in the soil to determine the influence of mulch on natural enemies, potential pests and soil macroinvertebrates, including earthworms.5 Collections sorted to family demonstrated that the addition of straw or compost mulches increased natural enemies collected with pitfall traps and soil organisms. However, there was no clear indication of the overall superiority of either mulch.6 Abundance of ground beetles, parasitoid Hymenoptera and spiders collected with pitfall traps were increased by the addition of mulches. In the canopy, predatory and parasitic Diptera and predatory Hemiptera increased after mulching.7 Earthworms collected by hand sorting soil increased with straw mulching.8 No influence on pests was detected. Although Lepidoptera and Sigmurethra, collected in pitfall traps, increased with straw mulching, neither included pest species.9 The results are discussed with reference to the potential economic impact of mulches.

Effect of Ground Cover by Different Crops on soil Loss and Physicochemical Properties of an Ultisol in South Eastern Nigeria.

Of all hazard factors, soil cover and cover management for conservations have the most important influences on the rain erosion hazard. The effects of ground cover by various crops on the soil physico-chemical properties and soil loss of an Ultisol in southeastern Nigeria were studied. Five experimental plots containing groundnut (Arachis hypogeal), maize (Zea mays), soyabean (Gylcine max), bambara groundnut (Vigna subterranean) and bare plot (control) were laid out in randomized complete block design (RCBD) and replicated three times. Five 15cm nails were randomly driven into the soil perpendicular to and leveled off with the soil surface to monitor soil removal by erosion. Results from this study showed that bare plots (no cover) had the highest topsoil loss of 2.40cm or 372 t ha-1 when compared with the plot with least topsoil loss (groundnut) which had 0.87cm of 134.8t ha-1. Similarly, plots planted with bambara groundnut and soyabean lost 1.95 and 1.83cm of topsoil corresponding to 302 and 283.6t ha-1 of topsoil loss respectively at 30days after planting (DAP). Similar trends were observed at 60 and 90 DAP. The least clay content was found in bare and bambara groundnut plots. Bare soil also had the least soil pH. Nigerian Journal of Soil Science Vol. 17 2007: pp. 94-97

(215) Effects of Groundcover and Drip Irrigation on Mineral Nutrition and Productivity of Sweet Cherry

The effects of in-row groundcover and drip irrigation on mineral nutrition and productivity of sweet cherry are largely unknown in the Pacific Northwest. A field experiment was initialized on the Mel Omeg orchard at The Dalles, Ore., in 2005. This orchard had been managed under microsprinkler irrigation and in-row herbicide application since its establishment in 1998. Two irrigation systems (drip irrigation, microsprinkler irrigation) and four in-row ground management systems (straw mulch, white fabric cover, black fabric cover, and no cover with herbicide applications) were evaluated in a split-plot design with four replicates. Drip irrigation reduced irrigation water consumption by 74% relative to microsprinkler during the entire season from May to September. Compared with no cover, black fabric lowered water use by 8%, and straw mulch and white fabric had a 1% to 3% reduction in water use. Fruit yield was similar for drip irrigation and microsprinkler. There was a trend of yield increase with groundcovers relative to no cover. Fruit firmness, size, and sugar content did not differ regardless of irrigation or groundcover systems. Drip irrigation increased marketable fruits by 5% (absolute value) via reducing fruit surface pitting compared with microsprinkler. Differences in soil-available N, P, K, Ca, Mg, S, B, Zn, Mn, Cu, pH, and organic matter were negligible between the two irrigation systems and among the four groundcover treatments. However, drip irrigation resulted in slightly lower concentrations of N, P, K, Ca, B, and Mn in leaf than microsprinkler. Overall, our results suggest that in-row straw mulch and fabric covers and drip irrigation could be feasible management alternatives for sweet cherry production in the Pacific Northwest.

Effects of Low-growing Perennial Ornamental Groundcovers on the Growth and Fruiting of `Seyval blanc' Grapevines

Greenhouse and field-grown `Seyval blanc' grapevines (Vitis sp.) were grown with low-growing, shallow-rooted, mat-forming, ornamental perennial groundcovers, and the effect of the groundcovers on the vegetative and fruiting growth of the grapevines was evaluated. The groundcovers used in this experiment were `Kentucky-31' tall fescue (Festuca arundinacea); white mazus (Mazus japoonicus albus); english pennyroyal (Mentha pulegium); dwarf creeping thyme (Thymus serpyllum minus); strawberry clover (Trifolium fragiferum); `Heavenly Blue' veronica (Veronica prostrata `Heavenly Blue'); and a companion grass mixture of 75% perennial ryegrass (Lolium perenne) and 25% red fescue (Festuca rubra). A control treatment grown without any groundcover was also used in both the greenhouse and field experiments. All of the groundcovers reduced `Seyval blanc' total shoot length from 22% to 85% in the vineyard. Cluster size was reduced in the field from 7% to 68% by the groundcovers compared to the herbicide control treatment, and from 9% to 66% in the greenhouse experiment, but none of the groundcovers in either the greenhouse or field experiments affected the pH, total acidity, or soluble solids concentrations of the `Seyval blanc' juice. English pennyroyal was the only groundcover that reduced in the leaf area of the grapevine. Single-leaf photosynthesis of the `Seyval blanc' grapevines in the field experiment was reduced by all groundcovers except mazus and creeping thyme. Water infiltration rates were 10 to 50 times higher in the groundcovers compared to the bare soil of the herbicide control treatment. Weed growth in the field caused reduction in shoot length similar to the most competitive groundcovers. Weed growth was reduced in the early season by the english pennyroyal and companion grass, and in the late season by all groundcovers. The reduction in growth of the grapevines caused by groundcovers in the greenhouse was a reasonable screen for the affect of groundcovers in the field. The mazus treatment was the only groundcover in our experiments that coupled fast growth with low competitive ability.

Glasshouse and field studies on the effects of groundcovers on banana and macadamia growth and water relations

Groundcovers can be useful for controlling erosion in macadamia orchards but they can have adverse effects on tree growth and crop yield. The effects of groundcovers versus bare soil on banana and macadamia were compared in a glasshouse study and on macadamia in the field. A glasshouse trial compared the effect of 3 water regimes with unmown or mown Arachis pintoi cv. Amarillo groundcover versus bare soil, on stomatal conductance and growth of banana and macadamia. Mean stomatal conductance was higher overall for macadamia (178 mmol/m2.s) compared with banana (90 mmol/m2.s) when data were pooled across groundcover and water treatments. Medium and dry substrate moisture treatments significantly reduced the growth and vigour of banana compared with the wet treatments, as indicated by reduced total dry matter, leaf area, number of live leaves at harvest, and total root length, but had no significant effect on macadamia. Groundcover had a more adverse effect on the growth of banana than macadamia compared with bare soil and, likewise, unmown cover had a greater effect on growth of banana than mown cover, while there was no mowing effect on macadamia.In an unirrigated field trial, mown and unmown groundcover and bare soil treatments were compared for their effect on early morning leaf xylem water potential of young and older macadamia trees at 3 sites where groundcover was established at different tree ages. Water potential was generally &lt;0.2 MPa more negative in the groundcover treatment than bare soil in spring and summer under dry seasonal conditions over 2 years, although there was no apparent effect on tree health. The difference in water potential between groundcover and bare soil was highest in young trees planted in established groundcover. The more adverse effect of groundcover on water status of young trees in established cover correlates with a greater reduction in growth compared with older trees reported separately (Firth et al. 2003 Aust. J. Exp. Agric. 43, 419–423).Soil bulk density under groundcover was slightly reduced (0.028 g/cm3) at 0–10 cm depth, and penetrometer resistance also slightly reduced (&lt;0.3 MPa) at 0–12 cm depth, compared with bare soil. Higher penetrometer readings in the traffic zone (often &gt;4 MPa at 30–40 cm in the initial survey) compared with the tree line indicate the potential long-term benefits to be derived from groundcovers.

Soil erosion assessment at the Udi-Nsukka Cuesta (southeastern Nigeria)

Biophysical and participatory research methods were combined to examine factors contributing to soil erosion at field plot, village and regional scale on the sandstone dominated Udi-Nsukka Cuesta in southeastern Nigeria. At field plot scale, the properties of seven pedons were related to soil erodibility. Very high infiltration rates measured with a double ring infiltrometer and permeameter, were not in accordance to reported runoff and soil loss. The effect of groundcover and canopy height was incorporated into rainfall erosivity for plots under cashew, oil palm dominated forest and secondary natural vegetation. Cropping systems and field management practices were compared for different positions along a toposequence traversing the plateau and escarpment of the Udi-Nsukka Cuesta. Soil loss, calculated by a modified version of the universal soil loss equation, was 10 to 100 times higher on escarpment than on plateau plots. Farmers are adapting to the problems of interrill and rill erosion through careful crop selection and rotation, and contour ridging. At the village and regional scale, terrain observations were compared to archival research, historical accounts by villagers and geographic analysis of 1962 aerial photographs (1:40 000). Ravine and gully formations seemed influenced by a combination of infrastructure, geohydrology, topography, vegetation and land use. Both community efforts and state measures to combat erosion tend to be crisis managed, and are concentrated on repairing damage to economically important infrastructures. A conceptual diagram has been developed to show the complex interaction between various geophysical, agroecological, socio-economic and political components influencing soil erosion at farm, village and regional scale. Copyright © 1999 John Wiley & Sons, Ltd.

A model for dispersal of plant pathogens by rainsplash

A mechanistic random ‘jump’ model is developed to describe the stochastic processes of splash dispersal of plant pathogens from a point source. In this model the main physical processes involved in the spatial spread of these spores are incorporated. That is, the probability per time unit that a spore is splashed λ, the probability that it then travels over some distance D(x), and the probability that it is not removed during this dispersal process ε. Numerical analysis shows the importance of ground cover and rain intensity on the model output. Factors influencing the process can be captured by changing the parameter values. For high rain intensities λ is large, therefore more spores are splashed; and, since ε is expressed per splash, simultaneously more spores will be removed from the system. The effect of ground cover is captured by ε its value decreases if the probability of staying in the process decreases. In addition, an equation is derived for the mean squared distance that spores splash. This equation shows a linear function independent of D(x). Finally, a diffusion approximation is developed for the mechanistic model and is compared to a diffusion model for splash dispersal developed by Yang et al. (1991a), New Phtol. 118, 295–301. The diffusion equation can only be considered a reasonable approximation to the full model under certain limiting conditions.

Effects of Orchard Ground Cover and Mite Management Options on the Population Dynamics of European Red Mite (Acari: Tetranychidae) and Amblyseius fallacis (Acari: Phytoseiidae) in Apple

Field experiments were conducted in 1992 and 1993 in an apple orchard to evaluate the effects of ground cover and management options on the population dynamics of the European red mite, Panonychus ulmi (Koch), and its predator, Amblyseius fallacis (Garman). In addition, the overwintering site of A. fallacis was investigated. Two orchard grass treatments, one mowed and the other unmowed, were compared with clean culture. Various treatments for control of P. ulmi were applied when economic thresholds were approached or exceeded. Treatments consisted of acaricides, horticultural oil, and release of predatory mites. Leaf samples were taken weekly, and changes in mite population dynamics were recorded throughout the growing season. The presence of ground cover had little effect on the number of A. fallacis or P. ulmi recovered from leaf samples in either year of the study. Even though predatory mites did use the ground cover for overwintering, a large number of A. fallacis were found overwintering directly on the tree. In 1993, two applications of horticultural oil resulted in a significantly lower prey-to-predator ratio than the acaricide treatment. Although the release of predatory mites resulted in higher A. fallacis numbers than the acaricide and horticultural oil treatments, it did not result in a lower prey-to-predator ratio than the untreated and horticultural oil.